The active matrix organic light-emitting diode (AMOLED) display is a new type display. In the conventional pixel driving circuit for the AMOLED, the driving architecture is generally designed similar to the conventional liquid crystal display (LCD). Pixel data are updated in column in time-sharing mode, and the mainstream of pixel driving mode is voltage compensation, and a gate voltage feedthrough effect may still be generated in the circuit architecture.
FIG. 1 is a schematic circuit diagram showing a driving circuit for an AMOLED. As shown in FIG. 1, the drain of an NMOS transistor M16 is electrically coupled to the data voltage Vdata, the gate is electrically coupled to the scanning voltage Scan, the source is electrically coupled to the terminal Vc1 of the storage capacitor Cst. The drain of the NMOS transistor M14 is electrically coupled to the terminal Vc1 of the storage capacitor Cst and the source of the NMOS transistor M16. The gate of the NMOS transistor M14 is electrically coupled to the discharge voltage Discharge, the source of the NMOS transistor M14 is electrically coupled to the terminal Vc2 of the storage capacitor Cst. The drain of the NMOS transistor M13 is electrically coupled to the source of the NMOS transistor M14 and the terminal Vc2 of the storage capacitor Cst, the gate of the NMOS transistor M13 is electrically coupled to the scanning voltage Scan. The drain of the PMOS transistor M11 is electrically coupled to the power voltage Vdd, and the gate of the PMOS transistor M11 is electrically coupled to the terminal Vc2 of the storage capacitor Cst, the source of the NMOS transistor M14 and the drain of the NMOS transistor M13. The source of the PMOS transistor M11 is electrically coupled to the source of the NMOS transistor M13. The drain of the PMOS transistor M12 is electrically coupled to the source of the PMOS transistor M11 and the source of the NMOS transistor M13. The gate of the PMOS transistor M12 is electrically coupled to the emitting control signal Emit, the source of the PMOS transistor M12 is electrically coupled to the OLED EL. The drain of the PMOS transistor M15 is electrically coupled to the reference voltage Vref, the gate of the PMOS transistor M15 is electrically coupled to the scanning voltage Scan, the source of the PMOS transistor M15 is electrically coupled to the terminal Vc1 of the storage capacitor Cst, the source of the NMOS transistor M16 and the drain of the NMOS transistor M14.
In the pixel driving circuit of FIG. 1, the NMOS transistor M16 is mainly used to write the data voltage Vdata at the data line to the pixel terminal Vc1. When Vscan is switched to low voltage level, voltage written to terminal Vc1 is decreased by 0.5˜1 Volts due to the feedthrough effect generated when turning off the transistor M16. In practical application, the feedthrough voltage changes with different written data voltages Vdata. In the pixel driving circuit of the AMOLED display, the written data voltage Vdata needs to convert to current for the OLED via the PMOS transistor M11 after compensation, since current driving is adopted in OLED to control the gray scales. The PMOS transistor M11 stays in saturation region when driving the OLED, as the result, the driving current for the OLED is affected by the actual input data voltage Vdata, which causes driving current difference for the OLED and thus causes color difference.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the disclosure and therefore it may contain information that does not form the prior art that is already known in this country to the person of ordinary skill in the art.